<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <div></div>
</body>
<script>
/*    var dv = document.getElementsByTagName('div')[0];
    dv.style.border = '1px solid red';
    dv.style.width = '100px';
    dv.style.height = '50px';
*/
/*
    var get = document.getElementsByTagName;
    var dv = get.call( document,'div' )[0];
    dv.style.border = '1px solid yellow';
    dv.style.width = '100px';
    dv.style.height = '50px';
*/
    var tmpFn = document.getElementsByTagName;
    var get = tmpFn.bind( document ); // 返回的还是函数
    var dv = get( 'div' )[0];
    dv.style.border = '1px solid red';
    dv.style.width = '100px';
    dv.style.height = '50px';

</script>
</html>